[Stuart]

I suspect that the problem is the way that Tescos (and the other supermarkets) run their stores.

In my experience, these stores are run by one or two people, probably on a minimum wage. At most, in my local Tesco Express, they've had someone on the tills, someone stacking shelves, a manager floating round and (sometimes) a guard on the door.

These people are generally busy, and are probably not looking to build a career in retail, so don't have much time for things like cleaning, and don't care much about the job if they do.

And, there's the problem of the councils. When I worked for our local blockbuster, we were reported to the local council and threatened with action over the pile of waste out the back of the shop.

Why was that waste there? It had built up over the previous month and a bit when the council (despite our complaints and reports) had consistently failed to pick up the rubbish. Normally our council is actually fairly reliable.